Collier won't be able to realize that dream because on Thursday evening he was shot and killed by brothers Tamerlan Tsarnaev and Dzhokhar Tsarnaev, the Boston Marathon bombing suspects, while responding to a reported disturbance on the MIT campus.

According to an Associated Press report, Collier was found shot several times in his vehicle in the area of Vassar and Main streets in Cambridge.

Collier had worked at MIT as a campus police officer since January 2012. He was a civilian employee of the Somerville Police Department prior to that.

MIT Police Chief John DiFava told Boston.com that Collier was well liked by both the MIT community and his fellow officers and that he was a dedicated officer.

Collier was a dedicated friend as well. He is remembered by his friends for his smile and sense of humor, as well as the ways he was there for his friends.

"Sean was such an amazing kid and would do anything to help someone," Chris Allison told MassLive.com. "He had an amazing sense of humor, and he was always smiling. It's such a shame that he was taken from us so prematurely, but he died a hero."

Collier's humor wasn't the only thing that defined him, though. He had a love of football, especially the New England Patriots, says his former roommate Dan Jenkins, 27. Jenkins, who is also working toward becoming police officer and currently works as a campus police officer at North Shore Community College, says Collier loved playing Madden on XBox and would often play with friends. He loved football, but not as much as he loved becoming a police officer.

Jenkins and Collier bonded over their passion for law enforcement, but Jenkins says Collier was more dedicated. The two friends worked security at the Liberty Tree Mall and Collier would take time to talk with the local police officers to learn from them, to listen to them.

"He had such a strong interest in doing the job," said Jenkins.

When Collier graduated from Salem State in 2009 with a degree in criminal justice with honors, he was an auxiliary police officer in Somerville, which, Jenkins explains, means he worked voluntarily. It was a resume builder, but it didn't pay the bills. At the same time, Collier worked as a reserve officer in Lincoln, Mass., where he worked numerous traffic details. Working as a reserve officer meant he didn't get benefits and only worked part-time.

Jenkins says Collier also paid for most of his own police training. He wasn't picked up by a department, so he had to dedicate his own time. He wanted to be a police officer and chased his dream.

"Sean self-sponsored [himself] into the police academy, which self-sponsoring takes a huge financial and time commitment," said Jenkins. "What a lot of the departments will do is pay for the academy, but Sean actually paid his own way and was that eager to get that training and get to the next step in that career."

When asked where that motivation came from, Jenkins said Collier just loved the job.

Collier's love for the job rubbed off on people at MIT.

"He wanted to do the job," said Jenkins. "He wanted to make arrests. He wanted to respond to any and all calls a law enforcement officer gets. He had a real interest in the profession.

Chief DiFava told Boston.com that Collier was a remarkable officer and person, that he was the same person in his uniform as he was in his regular clothes -- a funny, charismatic and committed individual. He also said Collier was able to overcome cultural barriers and integrate himself into the community at MIT, which is diverse.

“Besides this being absolutely heart-wrenching, it’s also a tremendous loss of a huge talent,” said DiFava.

Collier's family released a statement today recognizing the outpouring of support that has come from the people who Collier touched and impacted.

“We are heartbroken by the loss of our wonderful and caring son and brother, Sean Collier. Our only solace is that Sean died bravely doing what he committed his life to -- serving and protecting others. We are thankful for the outpouring of support and condolences offered by so many people," wrote the family.

A few months from possibly being promoted to his dream job, Collier died doing what he loved: being a police officer.